Expression and Localization of the Homeodomain-Containing Protein HEX in Human Thyroid Tumors

• Published in: The journal of clinical endocrinology and metabolism Vol. 87; no. 3; pp. 1376 - 1383
• Main Authors: D’Elia, Angela V, Tell, Gianluca, Russo, Diego, Arturi, Franco, Puglisi, Fabio, Manfioletti, Guidalberto, Gattei, Valter, Mack, David L, Cataldi, Palmina, Filetti, Sebastiano, Di Loreto, Carla, Damante, Giuseppe
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Copyright by The Endocrine Society 01.03.2002; Endocrine Society
• Subjects: Biological and medical sciences; Cell Nucleus - metabolism; Cytoplasm - metabolism; Endocrinopathies; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Humans; Malignant tumors; Medical sciences; Non tumoral diseases. Target tissue resistance. Benign neoplasms; RNA, Messenger - metabolism; Subcellular Fractions - metabolism; Thyroid Neoplasms - metabolism; Thyroid. Thyroid axis (diseases); Tissue Distribution; Transcription Factors; Tumor Cells, Cultured; Human; Immunohistochemistry; Papillary carcinoma; Liver; Anterior; Adenoma; Malignant tumor; Gene expression; Protein; Polymerase chain reaction; Tissue; Gene; Animal; Early; Earliness; Benign neoplasm; Localization; Cytoplasm; Endoderm; Localized
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.87.3.1376

Homeobox genes are involved in neoplastic transformation of both epithelial and hemopoietic tissues. The divergent homeobox gene HEX is expressed in the anterior visceral endoderm during early mouse development and in some adult tissues of endodermal origin, including liver and thyroid. Whereas a role in leukemyogenesis has been proposed already, few data are available on the involvement of HEX in human epithelial tumors. Herein, we analyzed HEX expression and subcellular localization in a series of 55 human thyroid tumors and in several tumoral cell lines. HEX mRNA was detected by RT-PCR either in normal tissues or in thyroid adenomas and differentiated (papillary and follicular) carcinomas. HEX mRNA was also expressed in most undifferentiated carcinomas. Subcellular localization of HEX protein was investigated by immunohistochemistry. In normal tissues and adenomas, HEX protein was present both in nucleus and cytoplasm. In contrast, both differentiated and undifferentiated carcinomas, as well as the tumoral cell lines investigated, showed HEX protein only in the cytoplasm. These findings suggest that regulation of HEX entry in the nucleus of thyrocytes may represent a critical step during human thyroid tumorigenesis.